Stitch-forming mechanism for shoe-sewing machines.



PATENTED FEB. 3, 1903.

J. L. KIBFFER. STITCH FORMING MECHANISM FOR SHOE SEWING MACHINES.

APPLIOATION'TILBD NOV. 18, 1901.

2 SHEETS-SHEET N0 MODEL.

Attorneys PATENTED FEB. 3, 1903.

. J. L. KIEFFER.

STITCH. FORMING MECHANISM FOR SHOE SEWINGMAGHINES.

APPLICATION FILED NOV. 18, 1901.

2 sums-sum 2.

N0 MODEL.

18 Ka K 6Z9 lnvento r,

Attorneys UNITED STATES PATENT OFFICE.

JOSEPH LOUIS KIEFFER, OF MONTREAL, CANADA.

STITCH-FORMING MECHANISM FOR SHOE- SEWING MACHINES.

SPECIFICATION forming part of Letters Patent No. 719,980, dated February 3, 1903. Application filed November 18, 1901. Serial No, 82,627. (No model.)

To all whom it may concern:

Be it known that I, JOSEPH LOUIS KIEFFER, a subject of His Majesty the King of Great Britain, residing' in the city and district of Montreal, Province of Quebec, Canada, have invented certain new and useful Improvements in Stitch-Forming Mechanism for Boot and Shoe Sewing Machines; and I do hereby declare that the following is a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to a stitch-forming mechanism especially adapted for shoe'sewing machinery of the lock-stitch type, which is especially adapted for outsole stitching that is to say, for stitching the sole to the welt in the process of making boots and shoes.

It is the main object of this invention to provide asubstitnte for the common shuttle method of making a lock-stitch that is to say, the method in which a rotating shuttle having a hooked point and carrying a bobbin is caused to revolve continuously and to catch the loop of the thread by the point thereof and pass it around the bobbin, whereby to link the bobbin-thread into the machine-thread, which operation forms the lock-stitch.

It is a furtherobject of my invention to improve the character of the lock-stitch by avoiding the twist incident to the employment of a rotary shuttle and which twist is caused to be taken in the machine or bobbin thread at the point where it links into the opposing thread, thus making it especially difficult to be drawn through the hole in the leather and to properly position thelock therein. In clothsewing machines in which this type of apparatus was originally used a twist in the thread adjacent to the look was highly advantageous, because the tenuous and pliable nature of the cloth would not holda plain loop against being pulled out by drawing upon one of the threads, and this feature has been engrafted into shoesewing machinery along with the apparatus which accomplishes it. In sewing leather, however, the operation is vastly different, because of the far greater thickness of the leather and also of its greater stiffness and unyielding nature, which not only makessuch a twist in the thread entirely useless, but actu ally disadvantageous,in the manner pointed out above, and, furthermore, it may be stated that it is necessary in stitching leather to position the lock of the thread very precisely between the two faces of the seam, and the twist caused by the looping process of the rotary shuttle prevents this being done.

In my improved stitching mechanism the loop of the machine-thread is drawn through the leather from the under side by an advancing and retreating hooked needle, as usual; butinstead of having the bobbin-thread passed through the loop thus formed to form the lock the reverse operation'is performed-that is to say, the loop is passed around the bobbin, the latter being held entirely stationary and loosely in a case or box formed with sufficient space on its sides to permit the loop of thread to be passed over and around the bobbin.

To these ends the important and essential feature of my present invention consists in an arcuate thread-hook having a forwardlydirected point adapted to enter the loop of the thread and a recnrved nose adapted to hook over and hold the same, and this arcuate thread-hook is caused by appropriate mechanism to oscillate in acircular raceway formed directly over the work and having the bobbin-case loosely held in a stationary position centrally thereof. This arcuate threadhook is caused to oscillate back and forth around the bobbin, and at each forward oscillation it is caused to pick up a loop of thread, whereupon its motion is reversed in such manner that the loop of thread retained by the nose of the hook is drawn out snfliciently to be passed completely around the bobbin, and as the backward motion of the hook continues it will become reversed in position, and the loop will fall away from the nose after being passed around the bobbin, whereupon the bobbin-thread will be found linked into the loop of the machine-thread, which is thereupon drawn taut and by appropriate mechanism pulled up to a sufficient extent to correctly position the lockin the seam.

An adjunctive feature of my oscillating thread-hook consists in forming the latter with a tail which has a groove formed theren so as to form a shield to cover the retreating hook end of the needle, this tail being formed to extend rearwardly around the raceway of the hook, so as to extend over and cover the needle at the time when the thread-loop is being drawn up and so as to keep it from becoming entangled with the hooked end of the needle.

The distinctive feature of my grooved point does not lie in the use of the groove, broadly, because heretofore other grooves have been employed for a similar general purpose in rotary shuttles; but the distinctive feature of my invention consists in the manner of delivering the thread from the barb of the needle, whereby the thread is prevented from becoming rubbed or abraded on the barb of the needle, and thereby weakened or frayed. The mode of operation will be hereinafter more distinctly pointed out in the detailed description.

Still another distinctive feature of this invention consists in the peculiar conformation of the point of the hook, which has a lateral curve on the inner side thereof, and the point is broadened out toward the nose and the curve deepened from front to back, so that as the point of the hook is inserted farther and farther into the loop the groove in said point will gradually surround the point of the needle and lift the thread clear of the hook thereof, thus enabling the thread to be drawn away from the needle by the backward movement of the oscillating hook.

My invention consists, further, in the peculiar construction and combination of parts, which are more particularly set forth in the accompanyingdescription and specifically defined in the claims.

My invention is illustrated in its most approved form in the drawings accompanying this specification, and wherein Figure 1 is a front elevation showing my stitch-forming mechanism in the act of completing a stitch. Fig. 2 is a central sectional elevation taken on the line 2 2 of Fig. 1. Figs. 3 and 4 are perspective views of the oscillating thread-hook looking from the front and rear sides, respectively. Figs. 5, 6, '7, 8, and 9 are front elevations of the stitch-forming mechanism, showing the successive positions assumed by the oscillatory thread-hook in the act of forming a stitch. Fig. 10 is a detail fragmentary view, partly in section and partly in elevation, taken upon the line 10 10 of Fig. 6. Fig. 11 is a similar view taken on the line 11 11 of Fig. 8. Fig. 12 is a central transverse vertical section through the bobbin and bobbin-case. Fig. 13 is a perspective view of the bobbin-case, showing the bobbin removed; and Fig. 14 is a similar perspective view of the bobbin, together with the retaining-screw and washer. Figs. 15 and 16 are views similar to Figs. 3 and 4 of a slightly-modified form of thread-hook.

The same numerals of reference denote like parts in all the figures of the drawings.

Referring first to Figs. 1 and 2, the numeral 17 designates a stationary block or head which is adapted to be mounted upon the front end of the machine directly over the work and in the relative position shown in the drawings. This block may be of any appropriate form suitable to the design or conformation of the machine, the form illustrated in Fig. 1 designating merely the general conformation which has been adopted by me in machines of my construction, and the face of this block is not truly vertical, but in ordinary practice has a downward and backward slant, as shown in Fig. 2, this being especially advantageous to permit the looping of the thread in the manner that will be hereinafter pointed out. In the center and lower part of the front face is formed a circular recess 18, the circumferential portions of which form a raceway for an arcuate thread-hook 19, which is caused by suitable means, to be presently described, to reciprocate 0r oscillate rapidly between two extreme positions around the circumference of the recess. The lower part of this raceway is cut away on both sides of the vertical central plane of the block through an angle of about ninety degrees, as shown at 20, this being for the purpose of permitting an arcuate needle (shown at 21 in Figs. 5, 10, and 11) to reciprocate back and forth therein and to cooperate with the point of the hook when it is projected into the open space 20.

Mounted centrally in the circular recess 18, so as to lie within and to be embraced by the raceway of the thread-hook, is a stationary bobbin-case 22, which is of a peculiar shape, as shown in Fig. 12, and incloses an ordinary spool or bobbin 23, on which is wound the bobbin-thread 24. The bobbin-case is not cylindrical in shape, but it has a flat back 25, which is sharply bent at an acute angle to form the annular conical portion 26, which, together with the outer head 27 of the'bobbin-spool, forms an inclosure within which the bobbin-thread is retained. The keel 28,- formed by the meeting of the fiat back 25 with the conical side 26, is somewhat rounded, as shown; but the curve connecting them is necessarily short in order to permit the easy slipping of the thread over the bobbincase and prevent it from catching around the circumference of the bobbin-case. The back plate 25 of the bobbin-case has centrally thereof a boss 29, through which is formed a screw-threaded aperture 30, wherein is mounted the stud 31 of the bobbin-spindle 32, which is turned to fit accurately the hub 33 of the bobbin or spool, so that the latter may be turned easily thereon without lost motion. In order to retain the spool in place, its outer head or flange 27 is recessed adjacent to the hub, as shown at 34, and in the annular re cess 34c fits a washer 35, which is secured to the spindle 32 by the screw 36, embedded therein. As herein shown, the hub 33 of the spool orv bobbin is made somewhat shorter than the length of the spindle in order to provide for a spider-shaped spring-plate 37, whose legs rest against the back plate 25 and are pressed forwardly against the .back end of the hub 33, so as to keep a certain amount of tension or friction upon the bobbin to prevent more thread from being uncoiled than is actually required in the operation of the machine. The edge of the conical side 26 of the bobbin-case is formed with an inwardlydirected annular rim 38, which is located close to the edge of the bobbin-spool, so as to shield the interior of the case against the entrance of dust or dirt, as shown in Fig. 12, and through the lower part of the conical face 26 there isformed an aperture 39 to allow the passage of the bobbin-thread 24, as shown, this passage being located opposite to the work being stitched.

The bobbin-case, holding the bobbin inclosed therein in the position shown in Fig. 12, is placed centrally within the recess 18, as shown in Figs. 1 and 2, and is held therein by a bracket 40, which has a T-lug 41 formed thereon immediately above the raceway, and this lug may be secured firmly to the face of the block 17 by nuts 42, threaded over stu ds 43, and this bracket is formed with a depending annular portion 44, whose interior face is formed conical, as shown at 44, to correspond with the conical side 26 of the bobbin-case, so that the ring 44 forms merely a loose support for the bobbin-case, which has considerable play within the recess 18 sufficient'to allow'the passage of the loop 45 of the machine-thread around the bobbincase.

As the bracket and the recess 18 are both slightly tipped forward, the bobbin-case containing the bobbin will naturally rest on the bracket and will under ordinary circumstances lie clear of the back, and to hold the bobbin-case against rotation it is formed with a projecting lip 46, depending from its lower.

side immediately in front of the thread-aperture 39, which lip engages with a corresponding recess or notch 47, formed in the ring 44, this notch being made somewhat larger than the lip 46, so as to allow a certain amount of play in order that the thread-loop maypass thereover easily.

The block 17 has an aperture extending therethrough in the central portion of the recess 18 and just behind the center of the bobbin-case, and through this aperture extends the front end 48 of the thread-hook arbor 49, which is mounted in a bearing block 50, formed integrally with the block 17 and directly behind the recess 18, but separated from the main portion of the block by a deep recess 51, in which turns the gear-pinion 60, by which power is transmitted to the arbor 49 to reciprocate the same through a geared segment 52, mounted upon a rock-shaft 53, which is caused to oscillate at the proper intervals by any suitable mechanism-such, for

instance, as a cam-lever working upon a camwheel on the main shaft of the machine. The

arbor 49 is secured in place in the bearingblock 50 by the nut 54, and it may be adjusted Fig. 10.

so that the front end protrudes just sufficiently into the recess 18 to support the bobbin-case in its proper position, while leaving room for the passage of the thread between the end 48 of the arbor and the bobbin-case, (see Fig. 2,) this end 48being formed with a slightly-projecting boss thereon for this purpose.

Projecting sidewise from the end 48 of the arbor 49 is the thread-hook arm 56, which is formed with a rectangular lug 57 upon its outer end, adapted to be secured by means of a screw 58 to the centralor waist portion of the thread-hook 19, which is provided with a mortise or notch 59, having dowel-pins 60, this conformation being clearly shown in Figs. 8 and 4. As thus constructed the arm 56 is adapted to be given a curvilinear reciprocatory motion by the oscillation of the arbor 49, and thereby in turn to reciprocate the threadhook 19 in its raceway through an arc of somewhat less than a complete circle.

Coming now to the form of the oscillatory thread-hook 19, which forms the most essen tial feature of my invention, this, as will be seen, is provided with a forwardly-directed tapered point 61, which is adapted to enter the nascent thread-loop and draw the same over the hook until it strikes therecurved nose 62 of the hook and is caught thereover in the bight 63. It will be observed that the nose 62 is located a considerable distance back of the point 61, and the shape of the hook between these two members is gradually widened out so as to spread the loop of the thread, and on the interior face of the hook is formed a deep groove 64, which extends from back of the nose forwardly toward the point, and is gradually tapered out, this groove 64 being positioned in the path of the hooked point 65 of the needle 21, so that when the hook is advancing the said groove will embrace the point 65 of the needle and draw the thread therefrom, as is more specifically shown in Back of the nose 62 isthe waist or central portion of the thread-hook, which is provided with a mortise 59, hereinbefore described, and rearwardly ofqthis waist portion is formed the arcuate tail 66, which is likewise provided with a lateral groove 67 on its interior face, this groove 67 being, as shown in Fig. 4, continuous with the groove 64 and being destined for a similar purpose--that is to say, to surround and shield the needle-point during the retreating movement of the book; but the groove 67 is not necessarily continuous with the groove 64, this being merely so shown in Fig. 4 for convenience in forming the book. The extremity of the tail 66 of the hook is tapered rearwardly, and the front face thereof is gradually brought down to the level of therear face, so as to produce a kind of forked portion 68, this tapered end being intended to project beneath or back of i the bobbin and loop threads 24 and 45, so as &

ment therewith while the loop is being drawn up. Although, as just mentioned, the groove 67 in the tail of the hook is shown in Fig. 4 as continuous with the groove 64 and as of the same shape therewith, yet it is not necessary that it should be of this shape, and to bring out this point I have illustrated a slightly-different form in Figs. 15 and 16, the forward groove in this figure being designated 64, which lies between the point 61 and the waist portion 59, and the groove 67' in the tail 66 has only one side, the lower edge of the groove shown in Fig. 4 having been cut away in this design, so that it will appear evident that the tail 66 serves no other purpose than a mere shield over the top and in front of the needle-hook.

- From the description given thus far the mode of operation will be sufficiently clear; but in order to clearly indicate the mode of forming a stitch the successive steps may be described as follows: After the hooked needle 21 has descended through the awl-hole made to receive it in the work 69 which is being stitched and has brought up a loop 45 of machine-thread to the position shown in Fig. 5 the forward motion of the thread-hook 19 will cause the point 61 thereof to enter the loop thus formed, as shown in Fig. 5. Upon further forward motion of the hook the loop 45 is opened out and spread, being at the same time drawn off of the hook of the needle by the sides of the groove 64 until finally the loop 45 passes over the nose 62 and becomes engaged in the bight 63, when the positions of the elements and thread are as shown in Fig. 6 in elevation and in central cross-section in Fig. 10. The thread-hook now commences its retreating movement and draws the loop 45 out into the successive positions shown in Figs. 7 and 1, in which latter position it will be observed that the loop partially surrounds the bobbincase and has begun to be drawn over the same. Continuing its backward movement the loop 45 is drawn entirely over the bobbincase and finally falls oi the nose 62 of the hook as it becomes reversed in position, as shown in Fig. 8. Just as this happens the tail-shield 66 comes into play by projecting over the hooked end of the needle 21, the tapered point 68 of the shield causing it to pass underboth threads of the loop and to press them outwardly free of the end 65, whereupon the action of the take-up mechanism in the machine rapidly draws the loop down into place, as indicated in Fig. 9, and the bobbin-thread is continually pulled inwardly to form the look within the seam, as shown at 70, and it is to be observed that the loop is so formed that the lock is plain-that is to say, there is no twist either in the bobbin-thread or the machine-thread in forming the lock, whereby the easy drawing up of the stitch into place is rapidly secured. During the operation of drawing up the thread-loop &5 it will be observed also that the slightlytipped position of the raceway and bobbincase causes the loop to be drawn outwardly out of the way of the needle, so as to clear the point thereof, this operation, together with that of the shield 66 in pushing the threads of the loop away from the needle, being clearly brought out in Fig. 11.

In connection with the mode of delivering the thread from the needle-barb by means of the groove 64 I desire particularly to point out the special manner in which this is done, which differs from that employed in certain rotary shuttles formerly invented which were provided with grooves into which the needle was caused to project, so as to deliver the thread-loop therefrom. In these former devices the barb of the needle necessarily faced in the direction of rotation of the shuttle, so that inasmuch as the shuttle had a continuous forward movement the thread was necessarily rasped over the sharp edge of the needle-bar just as it was withdrawn by the descent of the needle into the groove; but in my oscillating hook the barb of the needle faces in the contrary directionthat is to say, in the opposite direction from the advance movement of the hook-during which advance movement the thread loop is completely delivered from the needle and caught in the bight 63 of the hook, so that the thread is kept constantly pressed against the smooth shank and prevented from touching the edge of the barb at any time, and thereby abrasion is prevented.

While I have shown in the accompanying drawings the preferred form of my invention, it will be understood that I do not limit myself to the precise form shown, for many of the details may be changed in form or position without affecting the operativeness or utility of my invention, and I therefore reserve the right to make such modifications as are included in the scope of the following claims. 7

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A stitch-forming mechanism for shoesewing machines, comprising a barbed needle adapted to enter the work and bring up a thread loop therethrough, and an arcuate hook located on the same side of the work as the needle and adapted to oscillate and having a forwardly-directed point adapted to enter said thread-loop and a recurved nose adjacent thereto adapted to retain and draw out said thread-loop.

2. In a stitch-forming mechanism for shoesewing machines, a barbed needle adapted to enter the work and bring up a thread-loop therethrough, an arcuate thread-hook adapted to oscillate about an axis and having a forwardly-directed pointand means for retaining a thread-loop carried thereon, and a needle shield or guard carried on the rear end of said hook.

3. In a stitch-forming mechanism for shoesewing machines, a barbed needle adapted to enter the work and bring up a thread-loop therethrough, and an oscillatory thread-hook of arcnate form adapted to take said threadloop from the needle and having a grooved tail-shield for shielding the hooked needle.

4. In a stitch-forming mechanism for shoesewing machines,the combination of a barbed needle adapted to enter the work and bring up a thread-loop therethrough, an arcuate thread-hook provided with a forwardly-directed point, a recurved thread retaining nose, and an arcuate rearwardly-extending tail-shield adapted to cover the barbed point of the needle, and means for oscillating said thread-hook about its geometrical center.

5. In a stitch-forming mechanism for shoesewing machines,the combination of a barbed needle adapted to enter the work and bring up a thread-loop therethrough, a relatively stationary bobbin, and an arcuate hook located on the sameside of the work as the needle and adapted to oscillate around the bobbin and provided with a forwardly-directed point and a recurved thread-carrying nose adjacent thereto adapted to receive said thread-loop from the needle and carry it over the bobbin.

6. In a stitch-forming mechanism for shoe= sewing machines,the combination of a barbed needle, a relatively stationary bobbin, and an arcuate thread-hook located on the same side of the work as the needle and having a recurved nose on its inner side and a point adapted to enter and remove the thread from said needle and carry it around the bobbin.

7. In a stitch-formin g mechanism for shoesewing machines, the combination of a barbed needle, a relatively stationary bobbin-case loosely mounted in a box, a bobbin revolnble on a post within said case and adapted to carry thread, and an arcuate thread-hook located on the same side of the work as the needle and mounted to oscillate in a raceway around said bobbin and having a recurved nose on its inner side and a forwardly-directed point adapted to enter and remove the thread-loop from said needle and carry it around the bobbin.

8. A stitch forming mechanism for shoesewing machines, comprising a block having a raceway formed therein, a bobbin loosely retained in stationary position in the center of said raceway, a curved barbed needle adapted to enter the work and bring a threadloop therethrough, and an arcuate threadhook located on the same side of the work as the needle and reciprocating in said raceway and having means on its inner side for taking vloop of thread from the needle and carrying it around said bobbin.

9. A stitch-forming mechanism comprising a block having a circular raceway formed therein, a bobbin case containing thread loosely held in stationary position in the center of said raceway, a curved barbed needle adapted to enter the work and bring a threadloop therethrough, and an arcuate threadhook located on the same side of the work as the needle and adapted to reciprocate in said raceway around the bobbin, said thread-hook having a forwardly-directed point adapted to enter a loop of thread carried by the needle and a recurred nose adjacent to said point adapted to receive and draw out the loop and carry it over the bobbin, whereby to link said thread with the bobbin thread to form a stitch.

10. A stitch-forming mechanism comprising a block having a circular raceway formed therein, a bobbin case containing thread loosely held in stationary position in the center of said raceway, a curved barbed needle adapted to enter the work and bring a threadloop therethrough, and an arcuate threadhook adapted to reciprocate in said raceway around the bobbin, said thread-hook having a forwardly-directed point adapted to enter the thread-loop carried by the needle, a recurved nose adapted to engage and draw out said loop on the retreating movement of said hook and a rearwardly-extending tail-shield adapted to extend over and cover the barbed point of the needle during the drawing up of the thread-loop to prevent the latter from becoming entangled therewith.

11. A stitchJforming mechanism comprising a block having a circular raceway formed therein, a bobbin case containing thread loosely held in stationary position in the center of said raceway, a barbed needle adapted to carry a thread-loop, and an arcuate threadhook located on the same side of the work as the needle and adapted to reciprocate in said raceway around the bobbin, said threadhook having a forwardly-directed point adapted to enter and spread the thread-loop carried by the needle, a grooved inner face adapted to inolose the point of the needle and deliver the thread therefrom, and a recurved nose on its inner side adapted to engage and draw out the loop during the re-- treating movement of the thread-hook whereby tocarry it over the bobbin.

12. A stitch-forming mechanism comprising a block having a circular raceway formed therein, a bobbin case containing thread loosely held in stationary position in the center of said raceway, a barbed needle adapted to carry a thread-loop, and an arcuate threadhook adapted to reciprocate in said raceway around the bobbin, said thread-hook having a forwardly-directed point adapted to enter a thread-loop carried by the needle and spread the same, a longitudinal groove on itsinner face adapted to inclose the point of the needle and deliver the thread therefrom, a recurved nose adapted to receive and draw out the thread-loop on the retreating movement of the hook and to carry it over the bobbin, and a taper pointed tail-shield extending rearwardly of said hook adapted to cover the barbed point of the needle and to push away the thread therefrom during the drawing up of the loop.

13. A stitch-forming" mechanism comprising a block having a circular raceway formed therein, a bobbin-case containing a bobbin of thread loosely supported in a stationary position and centrally of said raceway, a curved barbed needle adapted to enter the work and bring a thread-loop therethrough, an arcuate thread-hook adapted to reciprocate in said raceway around the bobbin and having a forwardly-directed point adapted to enter and spread the thread-loop carried by the needle, a recurved nose adapted to engage and draw out said loop on its retreating movement and to carry it over the bobbin-case, and an arou- JOSEPH LOUIS KIEFFER.

Witnesses:

J A. MARION, T. MYNARD. 

